As one of the representatives of atheistic existentialism, Heidegger was the first philosopher to propose "existentialism" and promoted the systematization and clarification of existential theory. Taking the question of existence as the starting point, this book interrogates and discusses a series of philosophical propositions that Heidegger is concerned about (such as existence, time, truth, art, language, etc.). It strives to present the full picture of Heidegger's philosophical thoughts, clarify the structure of ideas and specific concepts, and break into the core and essence of each issue. The significance of this book is to help you gain an in-depth understanding of Heidegger's original philosophical thoughts and understand the origin and development of existential philosophy. It is suitable for beginners and readers who are interested in Heidegger's philosophy to read and study.